Center-friction for clocks and watches.



W. E. PORTER. CE NTER FRICTION FOR CLOCKS AND WATCHES.

- APPLICATION FILED OCT. 27. I913.

Patgnted Sept. 25, 1917.

UNITED STATES PATENT OFFICE.

WILSON E. PORTER, OF NEW HAVEN, CONNECTICUT, ASSIGNOR TO NEW HAVEN CLOCKCO., OF NEW HAVEN, CONNECTICUT, A CORPORATION.

CENTER-FRICTION FOR CLOCKS AND WATCHES.

Application filed October 27, 1913.

To all whom it may concern:

Be it known that I, VVILsoN E. PORTER, a citizen of the United States,residing at New Haven, in the county of New Haven and State ofConnecticut, have invented a new and useful Improvement in Center- Frictions for Clocks and Watches; and I do hereby declare the following,when taken in connection with the accompanying drawings and thecharacters of reference marked thereon, to be a full, clear, and exactdescription of the same, .and which said drawings constitute part ofthis application, and represent, in

Figure 1 a plan view of a center pinion for marine clocks and watches,provided with my improved friction device.

Fig. 2 a view thereof in front elevation.

Fig. 3 an enlarged view thereof in central longitudinal section with theexception of the center-arbor which is shown in plan.

Fig. 4 a plan view on the scale of Fig. 8, showing the parts assembledpreparatory to placing the friction washer under compression.

Fig. 5 a detached perspective view of my improved slotted washer havinga keyhole slot, shown as compressed.

My invention relates to an improvement in center frictions, so called,primarily designed for use in marine clocks and watches, the objectbeing to produce at a low cost for manufacture, a center frictionconstructed with particular reference to ease of assemblance andadjustment.

lVith these ends in view, my invention consists in a center friction formarine clocks and watches, having certain details of construction andcombinations of parts as will be hereinafter described and pointed outin the claims.

In carrying out my invention as herein shown, I employ a friction washer2 preferably made from a high grade of phosphor bronze and consisting ofa disk having a keyhole slot the round portion of which is concentricwith the periphery of the washer and the straight portion of whichextends radially outward therefrom. The washer as thus constructed, isnot a splitwasher, but a slotted washer, and is produced by removing aportion of its metal. The cut edges of the metal forming the walls ofthe slot and the ends of the washer are upset in opposite directionsfrom the plane thereof.

Specification of Letters Patent.

Patented Sept. 25, 1917.

Serial No. 797,541.

By slotting the washer I avoid the continsteel bearing washer 5 placedagainst the rear face of the inner head or collar 6 of a lantern pinionthe forward head or collar 7 of which has the center wheel 8 staked uponit. The heads or collars 6 and 7 are made integral with a fixed sleeve 9turning loosely upon the center-arbor 4 at a point thereon to the rearof its integral spacing shoulder 10 This the inner end of which isseparated by a steel washer 11 from the forward face of the head orcollar 7. The said heads or collars 6 and 7 are perforated in the usualianner for the reception of the short lengths of wire or needles 12which form the leaves of the pinion which, as shown, is of the lanterntype, though a cut-leaf pinion may be equally well employed inconnection with my invention. After the parts have been assembled asshown in Fig. 4, they are placed in a foot press and the adjustingcollar 3 is set down to its fixed position upon the arbor 4, whereby thefriction washer '2 is compressed after which it exerts a constant effortto push thev pinion forward on the arbor L with the effect of creatingsufficient friction between the forward head or collar 7 of the pinionand the washer 11 to normally bind the said pinion, and hence the wheel8, upon the arbor 4, so as to in sure their rotation together. However,for setting the hands, the arbor may be turned either by the hands whichare mounted upon its forward end or by a finger button 13 applied to itsrear end without turning the pinion or wheel within which the arbor thenrotates against the friction produced by the thrust of the washer 2.

I am aware that a considerable variety of friction washers haveheretofore been used for supplying the friction which, in my device, issupplied by the radially slotted washer 2, but all friction devicesheretofore with which they are engaged so that when the center arbor'isturned to set the hands, the springs will be slightly wound or unwound.Then when they recover and return to their normal condition, they willautomatically rotate the center arbor enough to move the hands in onedirection or the other, and so spoil the time. This objection may, tosome extent, be obviated by carefully fiattening and polishing the endsof the spring but the expense of so doing is prohibitive. Spiral springsare also objectionable because they take more longitudinal space thanmetal washers. The advantage of my slotted washer is that it is compact,never of itself eIt'ects the rotation of the center arbor in eitherdirection and may be properly set in a foot press without any subsequentadjustment or expenditure of time. In explanation of this laststatement, it should be explained that the friction developed by myslotted washer is substantially the same throughout the entire range ofits compression, beginning with its initial compression up to itscomplete compression. There will, of course, be a small gradual increaseof frictional power developed between initial and final compression, butthere is always suflicient compression for the friction required, at anypoint between initial and final compression. It follows from this thatall of the factors of variation in the size and thickness of the parts,and in the action of the foot-press may be disregarded since the washeracts, in-a sense, as a medium of universal compensation for all of thesevariations so that it becomes unnecessary to examine each center afterit leaves the foot press and complete the process of compressionmanually for each individual center as has heretofore been required inprior practice. In a factory turning out a large number of clocks orwatches per day, the saving of time by eliminating the necessity ofadjusting the tension of the center frictions makes a considerablesaving of expense.

1. A center friction for clocks and watches, characterized by theemployment of a sheetmetal friction washer having a key-hole slot theround portion of which is concentric with the periphery of the washerand the straight portion of which extends radially outward from the saidround portion and the ends forming the side walls of the slotted portionof the washer being offset in opposite directions from the plane of thewasher, the said washer being loosely mounted upon the center arbor ofthe clock-movement and interposed between an adjustingwasherfrictionally driven upon the said arbor and a bearing-washer engagedwith one end of a pinion loosely mounted upon the said arbor andcarrying the center Wheel of the movement, and the said washer beingcompressed by setting the adjusting-washer upon the center arbor andexerting a constant effort to hold the said pinion and wheel againstrotation thereupon, whereby the holding effect of the friction washer isobtained irrespective of the amount to which it is compressed short ofcompression to its initial flatness.

2. A center-friction for clocks and watches, characterized by theemployment of a sheetmetal friction washer having a key-hole slot wideenough to prevent the ends of the slot from coming into contact when thewasher is compressed to substantial flatness, the said washer having itsends offset in opposite directions from its plane and being looselymounted upon the center arbor of a clockmovement and interposed betweenan adjusting-collar mounted upon the said arbor and apinion looselymounted upon the said arbor, and the said washer being compressed bysetting the adjusting collar upon the arbor and when so compressed,exerting a constant effort to hold the said pinion against rotationthereupon.

In testimony whereof, I have signed this specification in the presenceof two subscribing witnesses.

WILSON E. PORTER.

Witnesses:

FREoERIo C. EARLE, MALCOLM P. NICHOLS.

Copies 01' this patent may be obtained for five cents each, byaddressing the Commissioner 0! Patents, Washington, D. 0.

